1. Problem solving among idiots.;Aldrich;Journal of Comparative Psychology,1931
2. Frustrative nonreward in partial reinforcement and discrimination learning.;Amsel;Psychological Review,1962
3. Effects of rewards upon the reaction times of mental defectives.;Baumeister;American Journal of Mental Deficiency,1967
4. The pooling mechanism and the phenomena of reinforcement.;Bevan,1963
5. Responses of normal and retarded children as a function of the experimental situation.;Bijou;Psychological Reports,1960